Extraction of an Entanglement by Repetition of the Resonant Transmission of an Ancilla Qubit

TL;DR

This paper proposes a scheme to extract entanglement between two noninteracting qubits by repeatedly transmitting an ancilla qubit resonantly, eliminating the need for ancilla preparation or post-selection.

Contribution

It introduces a novel entanglement extraction method using resonant transmission controlled by the qubits' entanglement, without requiring ancilla preparation or post-selection.

Findings

Successfully extracts singlet state from arbitrary initial states

No ancilla preparation or post-selection needed

Efficient entanglement extraction through repeated resonant transmission

Abstract

A scheme for the extraction of entanglement in two noninteracting qubits (spins) is proposed. The idea is to make use of resonant transmission of ancilla qubit through the two fixed qubits, controlled by the entanglement in the scatterers. Repetition of the resonant transmission extracts the singlet state in the target qubits from their arbitrary given state. Neither the preparation nor the post-selection of the ancilla spin is required, in contrast to the previously proposed schemes.